System for balancing a two-wheeled vehicle at rest

ABSTRACT

A system ( 10 ) for balancing two-wheeled vehicles when approaching rest or when at rest is provided. The system ( 10 ) includes a spinning gyro rotor ( 12 ) which is precessed about an axis ( 16 ) upon the sensing ( 22 ) of incipient tipping of the vehicle when the vehicle is at rest or approaching rest so as to generate a force for preventing such tipping. The system may be packaged in a small module ( 100 ) that can be mounted on existing two-wheeled vehicles.

FIELD OF THE INVENTION

[0001] The present invention relates to a system for balancing atwo-wheeled vehicle and specifically to a system incorporating aselectively precessed spinning gyro rotor for balancing two-wheeledvehicles when about to stop or when stopped.

BACKGROUND OF THE INVENTION

[0002] Two-wheeled vehicles such as motorcycles and bicycles generallycreate gyroscopic forces while their wheels are rotating keeping thesevehicles in balance. These vehicles become unstable and will tip ontheir sides when stopped unless the rider puts a foot on the ground orpavement for stability. This “grounding” of the rider is a nuisancewhich riders will go to great lengths to avoid. Putting a foot down isboth objectively and subjectively undesirable in that it detracts fromboth the utility and sense of freedom of these vehicles.

[0003] The general use of gyros to stabilize a vehicle is known.However, these gyros tend to be continuously precessed in order tobalance the vehicle. Consequently, these gyros are always generatingforces interfering with the operation of such vehicles. As a result,two-wheeled vehicles incorporating these devices have problems whensteering, especially when banking the vehicle to make a turn since thegyro generated forces will have the tendency to upright the vehiclethereby putting the rider in a dangerous situation.

[0004] Other gyros used to stabilize two-wheeled vehicles are coaxiallymounted within the wheel of such vehicles. These spinning gyros are notprecessed and therefore are ineffective in balancing the two-wheeledvehicle. Another problem with many gyro systems in use today is thatthey may be difficult to incorporate it into an existing vehicle.

[0005] As such, a system is needed for generating forces for keeping atwo-wheeled vehicle in balance while at low speeds approaching a stop orwhen stopped and which do not generate forces when the vehicle istraveling so as to not interfere with the operation of the vehicle.Moreover, a system is needed that can be easily incorporated intoexisting vehicles.

SUMMARY OF THE INVENTION

[0006] A system for balancing two-wheeled vehicles is provided. Thesystem includes a tipping sensor for detecting the incipient tipping ofa two-wheeled vehicle. The system also includes a small gyro rotortypically weighing less than 10 pounds, a motor for spinning the gyrorotor, and a precession device for precessing the gyro rotor about anaxis perpendicular to the spin axis. The system further includes avelocity sensor or may receive input from the vehicle speed measuringequipment such as a speedometer. A controller receives information fromthe tipping and velocity sensors.

[0007] The system allows for the selective precession of the gyro rotor.The motor spins the gyro rotor at high RPMs, e.g., 25,000 RPM. When thetwo-wheeled vehicle is stopped or is about to come to a stop (i.e., whenits speed is less than a minimum predetermined speed) and begins to tip,the tipping sensor senses the incipient tipping of the vehicle.Simultaneously, the controller activates the precession device forrapidly precessing the spinning gyro rotor (e.g., 100 radians/sec. ormore) in a direction for generating a force counterbalancing thetipping. The precession device then returns or allows the precesses gyroto return to its original non-precessed position. While the vehicle istraveling, the gyro rotor is not precessed thereby preventing thegeneration of forces that would interfere with the normal operation ofthe vehicle as in the case when the vehicle is tipped during turning.

[0008] By spinning the gyro rotor at high RPMs and precessing it at ahigh angular velocity, e.g., “hurrying” the precession to generate anappropriate anti-tipping force, a small gyro rotor may be used forbalancing the two-wheeled when stopped or about to stop. As such, theinventive system can be packaged in a small package that can bepurchased as a separate accessory for mounting onto an existingtwo-wheeled vehicle. To allow the gyro rotor to obtain high RPMs, it ispreferred that the spinning gyro rotor is packaged in at least a partialvacuum. The system can also be incorporated into two-wheeled vehicles atthe time of manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a schematic view of a two-wheeled vehicle balancingsystem of the present invention.

[0010]FIG. 2 is a schematic view of one embodiment tipping sensorincorporated in the present invention.

[0011]FIG. 3 is a front end view of a two-wheeled vehicle with rider ina tilted balanced condition maintained due to cross-winds.

[0012]FIG. 4 is a front end view of a two-wheeled vehicle with rider ina tilted balanced condition due to a rider weight shift.

[0013]FIG. 5A is a front view of another embodiment tipping sensorincorporated in the present invention for sensing tipping of atwo-wheeled vehicle from a balanced condition.

[0014]FIG. 5B is a side view of the tipping sensor shown in FIG. 5A.

[0015]FIG. 6 is an end view of a gyro rotor and motor for precessing thegyro rotor about an axis offset from the center of gravity of the gyrorotor.

[0016]FIG. 7A is a side view of a gyro rotor on a gimbal which iscoupled to two solenoids for rotating the gimbal and precessing the gyrorotor about an axis offset from the center of gravity of the gyro rotor.

[0017]FIG. 7B is an end view of the gyro rotor with precession meansshown in FIG. 7A.

[0018]FIG. 8A is a schematic view of a modular system for balancingtwo-wheeled vehicles of the present invention.

[0019]FIG. 8B is an end view of the modular system shown in FIG. 8A.

[0020]FIG. 9A is a side view of the motorcycle with a modular system ofthe present invention coupled to the motorcycle frame.

[0021]FIG. 9B is a side view of a motorcycle with a modular system ofthe present invention coupled to the motorcycle frame.

DETAILED DESCRIPTION

[0022] A two-wheeled vehicle balancing system 10 is provided thatincorporates a small gyro rotor 12 typically weighing less than 10 lbs.(FIG. 1). The system is mounted on a two-wheeled vehicle. The rotor ismounted on the vehicle via a gimbal 15 so that it rotates about itscentral axis 14 and so that it can precess about a precess axis 16perpendicular to the central axis. The precess axis may intersect thecenter of gravity 86 of the gyro rotor as shown in FIG. 1 or it may beoffset from the center of gravity of the gyro rotor as shown in FIGS. 6and 7B.

[0023] A motor 18, e.g., an electric motor is used to spin the rotor 12mounted on the gyro gimbal 15. The electric motor may obtain electricityfrom the vehicle's electrical system or the vehicle's battery. A servoor other mechanical, electrical or electro-mechanical device 20 is usedto rapidly precess the spinning gyro rotor about its precess axis 16. Atipping sensor 22. The system also includes a controller 24 whichreceives signals from the tipping sensor indicative of whether thevehicle is tipping. The controller is also coupled to a velocity sensorsuch as the vehicle's speedometer 26 from which it continuously receivessignals indicative of the vehicle velocity.

[0024] The controller sends a signal to the precessing device 20 forprecessing the gyro in a direction to counteract the vehicle tippingwhen the controller receives a signal from the velocity sensorindicating a vehicle velocity that is lower than a predeterminedvelocity and when it receives a signal from the tipping sensor denotingincipient tipping of the vehicle and the tipping direction. Thepredetermined velocity may be programmed into the controller. Thepredetermined velocity is preferably a low magnitude velocity such thata velocity magnitude below the predetermined velocity is indicative thatthe vehicle is close to being stopped.

[0025] As the two-wheeled vehicle slows down sufficiently and beginstipping, the system kicks in, i.e., the spinning gyro rotor is precessedgenerating a sufficient force to keep the vehicle upright while at slowspeeds and while fully at rest. Typically, the precession of the gyrogenerates a force that is slightly greater than that needed to uprightthe vehicle, i.e., the gyro rotor is over precessed, thereby causing thevehicle to attempt to tip the other way. Consequently, the gyro rotor isprecessed in the reverse direction to overcome such tipping. As aresult, the gyro may be go through a series of rapid cyclic precessionsfor providing a sufficient force for keeping the vehicle upright.Typically, the cyclic precessions occur over a period less than severalmilliseconds. The gyro returns to its original non-precessed positionbetween each precession. If the vehicle were to begin tipping again, asfor example, when in a prolonged stop, the gyro rotor is again precessedto overcome the incipient tipping and returns to its original positionafter generating sufficient force for keeping the vehicle upright. Thegyro rotor may be precessed and returned to its original positionmultiple times for maintaining the vehicle in an upright position whenabout to stop or when stopped. The gyro rotor may be continuously spunwhen the vehicle is in operation or it may be selectively spun as thevehicle speed drops below a preselected speed.

[0026] In one embodiment, the tipping sensor 22 comprises a spinningrate gyro rotor 30 (FIG. 2). As the vehicle tips, the spinning rate gyromaintains its position relative to the ground due to the forces itgenerates by spinning. Sensors 32 may be positioned so as to becontacted by a probe 36 extending from the gyro mounting frame or gimbal38. As the vehicle tips in one direction, the probe 36 comes in contactwith one of the sensors 32 and when the vehicle tips in the oppositedirection the probe 36 comes into contact with the other sensor 32. Thesensors 32 are coupled to a sensor controller 23 which ascertains whichsensor 32 was contacted and which then sends a signal to the systemcontroller 24 indicative of tilting and the direction of tilting.Alternatively, the sensors may be coupled directly to the systemcontroller 24 as denoted by the dashed lines in FIG. 2. In an alternateembodiment, a circuit may be mounted on the rate gyro mounting frame orgimbal that is broken as the mounting frame or gimbal rotates as thevehicle tips. Such circuit may also be coupled to a sensor controller ormay be coupled directly to the system controller 24.

[0027] There may be situations where the two-wheeled vehicle 40 andrider 42 may be in a tilted position with the two-wheeled vehiclebalanced. For example, as shown in FIG. 3, the two-wheeled vehicle maybe balanced even though it is inclined relative to the pavement at anincline angle 44 less than 90°. This may occur when the vehicle is atrest and is subject to cross-wind 43. The cross-wind balances thevehicle in the inclined position depicted in FIG. 3. A balanced but notupright condition may also occur when a rider 42 of the two-wheeledvehicle 40 shifts his/her weight in one direction causing the vehicle toshift in the opposite direction for balancing the vehicle as shown inFIG.4.

[0028] If the two-wheeled vehicle is about to stop or is stopped whenthe vehicle is tilted but balanced as described above, the tippingsensor would sense the incipient tipping and the system of the presentinvention would precess the spinning gyro rotor to upright the vehicle.However, when this occurs, the force provided by the precessing gyrorotor will tend to put the vehicle out of balance in the direction ofthe force provided by the precession of the gyro. Consequently, the gyrowill then precess in the opposite direction by the system to overcomethis unbalancing.

[0029] Once at the upright position, the force created by the wind 43(FIG. 3) or by the weight of the shifted rider 42 (FIG. 4) will tend toput the vehicle out of balance. This will cause the system to precessthe gyro rotor in the opposite direction from its previous precession.Consequently, the gyro will undergo cyclic precessions for maintainingthe vehicle in a balanced position. In other words, the gyro willprecess in one direction and then return to its original position, thenprecess in a second opposite direction and return to its originalposition, then precess in a direction opposite second direction andreturn in its original position, and so forth. In an effort to avoid thesuch cyclic precessions, a tipping sensor may be used that sensesincipient tipping from a balanced position of the vehicle even when thevehicle is tipping, thus causing the system to apply correctiveup-righting forces to the vehicle only when the vehicle is out ofbalance. In other words, such a tipping sensor senses relative tippingfrom a balanced tilted position.

[0030] One such sensor is a compensating pendulum sensor 50 shown inFIGS. 5A and 5B. This sensor comprises a compensating pendulum orgravity pendulum 52 which is basically a pendulum that maintains itsorientation relative to the ground due to its inertia. The pendulum ismounted on the two-wheeled vehicle 40 such that it can pivot to maintainits orientation relative to the ground as the two-wheeled vehicle tips.This can be accomplished by mounting the pendulum such that it can pivotalong a plane perpendicular to the longitudinal axis of the two-wheeledvehicle.

[0031] The compensating pendulum sensor also comprises a contact lever54 that is coupled to the pendulum via a viscous fluid coupling 56.Typically the proximal ends 58 and 60 of the pendulum and contact lever,respectively are coupled to the viscous coupling 56 as shown in FIG. 5Bsuch that they extend radially outward from the viscous coupling.

[0032] The viscous coupling comprises a first member 64 and a secondmember 66. The two members are rotationally coupled to each other by aviscous fluid 68. In the embodiment shown in FIG. 5B, the first member64 is disk shaped member. The second member 66 defines a housing in theshape of a short cylinder. The first member 64 and the viscous fluid 68are housed within the second member 66. In this regard, the first member64 is surrounded by the viscous fluid. The first member is able torotate relative to the second member subject to frictional constraintsimposed by the viscous fluid.

[0033] The pendulum 52 is coupled to one member and the contact lever iscoupled to the other member of the viscous coupling. In the embodimentshown in FIGS. 5A and 5B, the pendulum 52 is connected to the firstmember 64 and the contact lever 54 is connected to the second member 66of the viscous coupling and are able to pivot i.e., rotate relative toeach other about a pivot axis 70. The entire compensating pendulumsensor is pivotally coupled to the two-wheeled vehicle about the pivotaxis 70.

[0034] Two opposing springs 72, 74 are coupled proximate the distal end76 of the contact lever 54 and to the two-wheeled vehicle 40. The firstspring 72 exerts a force on the contact lever opposite the force exertedby the second spring 74 so as to maintain contact lever in a balancedposition between the two springs as shown in FIG. 5A. Two electricalcontacts 78, 80 are situated on either side of the contact leverproximate the contact lever distal end 76 and are spaced apart from thecontact lever when the lever is in a balanced condition. In this regard,as the contact lever pivots in one direction it will come in contactwith one of the electrical contacts and when it pivots in the oppositedirection it will come in contact with the other electrical contact.When in the balanced position, the contact lever is not in contact withany of the electrical contacts 78, 80. By monitoring or receiving asignal of contact between the contact lever and an electrical contact, adetermination as to which direction the two-wheeled vehicle is tippingcan be made. Contact of the contact lever with one of electricalcontacts is indicative of tipping in one direction while contact withother contact is indicative of tipping in the opposite direction. Thetwo contacts may be coupled to a tipping sensor controller or directlyto the system controller.

[0035] As the two wheeled vehicle tips, it simultaneously causes thependulum to rotate. As the pendulum rotates it causes the contact leverto also rotate in the same direction (e.g., clockwise orcounter-clockwise) as the viscous fluid initially prevents (i.e.,restricts) relative rotation between the two members of the viscouscoupling. When the contact lever rotates it will come in contact withone of the electrical contacts while stretching one of the springs. Thestretched spring, thus, provides a force for returning the contact leverback to the balanced position. If the two wheeled vehicle remains in thetilted position, as for example described herein in relation to FIGS. 3and 4, the pendulum attempts to remain oriented to the ground while thecontact lever is under a force created by the springs for maintainingthe lever in the balanced position, thereby generating a torque betweenthe two members of the viscous coupling which slowly overcomes thefriction force of the viscous fluid. Consequently, the two members torotate relative to each other such that the contact lever is caused toreturn to the balanced position by the stretched spring and is retainedin the balanced position by the springs, while the pendulum is orientedto the ground. In this regard, if the two wheeled vehicle remains in atitled but balanced position, the compensating pendulum sensor will notprovided a signal of incipient tipping and thereby will not instigate anunnecessary precession of the gyro and the creation of an unnecessaryuprighting force.

[0036] Other types of viscous couplings may be incorporated with thecompensating pendulum sensor described herein. Moreover, instead ofextension springs (i.e., spring which provide a force when extended)compression springs (i.e., springs that provide a force when compressed)may be incorporated in the compensating pendulum sensor. Furthermore,other types of tipping sensors may be used that will not indicate atipping of the two wheeled vehicle, when the vehicle is tilted butbalanced.

[0037] In a further embodiment, a pendulum sensor not incorporating theviscous coupling may be used, i.e., the contact level may be connectedor be integral with the pendulum for sensing tipping of the two-wheeledvehicle without compensating for tipping but balanced conditions of thetwo-wheeled vehicle. In addition other electrical, mechanical orelectro-mechanical tipping sensors may be incorporated in the system.

[0038] The precessing device 20 for precessing the gyro can be a servo,a motor or one or more solenoids. In one embodiment as shown in FIGS. 1and 6, a motor is used to precess the gyro rotor 12 about a precessionaxis 16 perpendicular to the spin axis 14 of the rotor. The motor 21 maybe coupled to the gyro gimbal 15 via gears 82. The precession axis 16may be through the center of gravity 86 of the gyro rotor 12 as shown inFIG. 1 or may be offset from the center 86 as shown in FIG. 6. Whentipping is sensed by the tipping sensor 22, the controller 24 sends asignal to the motor for quickly precessing the gyro rotor for creating aforce to counteract the tipping force and then immediately sends asecond signal to the motor for returning the gyro rotor in its originalnon-precessed position. In the alternative, the motor may be of the typewhich would allow the precessed gyro rotor to return to its originalposition under its own gyroscopic inertia as for example when the motordoes not receive a signal from the controller for precessing the gyro.

[0039] In an alternate embodiment shown in FIGS. 7A and 7B, twosolenoids 88, 90 are used to precess the gyro. The solenoids may be ofthe type that extend or the type that retract when actuated. The twosolenoids are oppositely coupled to the gyro gimbal 15 via a control arm92. The control arm 15 is coupled to the gimbal 15 and extends from thegimbal in a direction preferably parallel to the spin axis 14 of thegyro. Specifically, the solenoids are oppositely coupled to the controlarm 92 as shown in FIG. 7B. In this regard, when one solenoid isactivated it causes the control arm and thus the gimbal and gyro rotorto precess in one direction and when the other solenoid is activated itcauses control arm and thus the gimbal and the gyro rotor to precess inthe opposite direction about a precess axis 16. When incipient tippingis sensed, the controller 24 sends a signal to one of the solenoidswhich extends (or retracts) for precessing the gyro to generate a forceto counteract the tipping of the vehicle. Immediately a follow up signalis send to the other solenoid, which extends (or retracts) forprecessing the gyro rotor back to its original non-precessed position.

[0040] In an alternate embodiment, one solenoid may be used which iscoupled to the control arm 92 and which may be controlled for extendingand retracting for precessing the gyro rotor in both directions and forreturning the gyro rotor to its original non-precesses position. In yeta further embodiment, a single solenoid may be used which is coupled tothe control arm and which either extends or retracts for precessing thegyro when receiving signal from the rotor and when it does not receive asignal it allows the rotor to return to its original non-precessedposition under its own gyroscopic inertia.

[0041] By precessing the rotor only when the vehicle is about to stop orwhen the vehicle is stopped and by returning the precessed rotor to itsoriginal position after each precession, the system insures thatanti-tipping forces are not provided by the system when the two-wheeledvehicle is in motion and is banked as for example during a turn.Furthermore, by providing the force to upright the two-wheeled vehicleupon incipient tipping, the force required to bring the vehicle to anupright position is minimized thus minimizing the size of the gyro rotoris minimized.

[0042] The physics of gyroscopic operation dictates that the rotorweight required for generating a predetermined force is a function ofthe rotor spinning RPMs, rotor diameter, rotor shape and precession rate(angular velocity) about an axis perpendicular to the spin axis inradiants per second “dv/dt”. Reducing, the rotor size is therefore amatter of increasing both the rotor RPMs and the precession rate. In apreferred embodiment of the present invention, the rotor is spun at highRPMs and a high precession rate is achieved. For example, a 5 inchdiameter, 1 inch thick rotor spinning at 25,000 RPMs and having aprecession rate of 100 radius per second would create a anti-tippingforce in the order of 55 foot pounds. This force may be sufficient tocounteract the incipient tipping forces of the vehicle as it comes torest. To achieve high RPMs, the rotor is preferably housed and spun in apartial vacuum.

[0043] Consequently with the inventive system, a gyro rotor that weighsless than 10 lbs. is sufficient for generating the requisite forces.This is unlike traditional gyro rotors which are used to stabilizevehicles which typically have a weight of about 5% of the total vehicleweight. For example, in the case of a 900 lb. motorcycle and a 250 lb.rider, under conventional systems a 58 lb. gyro rotor would have to beused. With the present invention, however, a gyro rotor weighing lessthan 10 lbs. may be used to keep the same vehicle with rider balanced.

[0044] The entire gyro system described herein can be incorporated in asmall module or housing 100 that can be easily attached to anytwo-wheeled vehicle FIGS. 8A, 8B, 9A and 9B. For example, the housingpreferably includes a vacuum chamber 102, capable of achieving at leasta partial vacuum, for housing the rotor so as to allow the rotor to spinat high RPMS. The motor 18 may also be housed in the vacuum chamber 102as shown in FIG. 8B. The precession device 20, the tipping sensor 22 andthe controller 24 may be housed in a separate chamber 104 as shown inFIG. 8A or may be housed in the vacuum chamber 102. If two chambers 102,104 are incorporated in the module 100 as shown in FIG. 8A, a seal 106is used around a portion of the gimbal 15 extending from the vacuumchamber 102 to the second chamber 104 for coupling with the precessiondevice 20. The module can be mounted on a two-wheeled vehicle such as amotorcycle 108 chassis as for example shown in FIGS. 9A and 9B ensuringthat the tipping sensor 22 is properly oriented for sensing incipienttipping. Input from the speedometer is then coupled to the controller.Alternatively, the module may incorporate its own velocity sensor sothat it does not have to rely on the speedometer of the vehicle. As canbe seen, the entire system could be an accessory that can beunobtrusively attached to the two-wheeled vehicle.

[0045] Although the present invention has been described and illustratedwith respect to multiple embodiments thereof, it is to be understoodthat it is not to be so limited, since changes and modifications may bemade therein which are within the full intended scope of this inventionas hereinafter claimed.

1. A system for balancing a two-wheeled vehicle when approaching rest orwhen at rest comprising: a gyro rotor; a motor for spinning the gyrorotor; a tipping sensor for sensing tipping of the vehicle; a precessionmeans for precessing the gyro rotor from a first not precessed positionto a second precessed position and for facilitating the return of theprecessed gyro to the first position; a controller coupled to thetipping sensor and precession means and for receiving informationrelating to the velocity of the vehicle, wherein the controller controlsthe precessions means for precessing the gyro from the first to thesecond position when the tipping sensor has sensed tipping and when thevelocity of the vehicle is not greater than a predetermined minimumvelocity, and for immediately returning the gyro rotor from the secondto the first position.
 2. A system as recited in claim 1 wherein thetipping sensor can sense the direction of tipping.
 3. A system asrecited in claim 1 further comprising a housing encasing the gyro rotor,tipping sensor, motor and precession means, said housing and gyro,tipping sensor, precession means and motor defining a module formounting on the vehicle.
 4. A system as recited in claim 3 wherein thehousing comprises at least a partial vacuum chamber and wherein the gyrorotor is housed within said at least partial vacuum chamber.
 5. A systemas recite in claim 1 wherein the precession means comprises a motor. 6.A system as recited in claim 1 wherein the precession means comprises asolenoid coupled to the rotor.
 7. A system as recited in claim 1 whereinthe solenoid means further comprises a second solenoid coupled to therotor, wherein one solenoid precesses the rotor in one direction and theother solenoid precesses the rotor in the opposite direction.
 8. Asystem as recited in claim 1 wherein the gyro rotor returns to the firstposition under its own gyroscopic inertia.
 9. A system as recited inclaim 1 wherein the tipping sensor comprises a gyro which maintains aposition relative to a ground during tipping of the vehicle.
 10. Asystem as recited in claim 1 wherein the tipping sensor comprises apendulum, wherein the pendulum pivots to maintain its position relativeto the ground during tipping.
 11. A system as recited in claim 1 whereinthe tipping sensor senses relative tipping.
 12. A system as recited inclaim 1 wherein the tipping sensor comprises: a viscous coupling; apendulum coupled to the viscous coupling for maintaining it positionrelative to a ground during tipping of the vehicle; an arm coupled tothe viscous coupling and extending opposite the pendulum, wherein theviscous coupling allows the arm to pivot relative to the pendulum; afirst spring coupled to an end of the arm distally from the viscouscoupling, the first spring being capable of providing a first force forpivoting the arm in a first direction; a second spring coupled to an endof the arm distally from the viscous coupling, the second spring beingcapable of providing a second force opposite the first force to the armfor pivoting the arm in a second direction opposite the first direction;a first contact coupled to the controller; and a second contact oppositethe first contact and coupled to the controller, wherein contact of thearm with the first contact is indicative of vehicle tipping in onedirection and wherein contact of the arm with second contact isindicative of vehicle tipping in the opposite direction.
 13. A system asrecited in claim 1 wherein the gyro rotor has a weight not greater than10 lbs.
 14. A system as recited in claim 1 further comprising a velocitysensor coupled to the controller for sending information to thecontroller relating to the velocity of the vehicle.
 15. A self-balancingtwo-wheeled vehicle comprising: a gyro rotor; a velocity sensor; a motorfor spinning the gyro rotor; a tipping sensor for sensing tipping of thevehicle; a precession means for precessing the gyro rotor from a firstnot precessed position to a second precessed position and forfacilitating the return of the precessed gyro to the first position; acontroller coupled to the tipping sensor, the velocity sensor andprecession means, wherein the controller controls the precessions meansfor precessing the gyro from the first to the second position when thetipping sensor has sensed tipping and when the velocity of the vehicleis not greater than a predetermined minimum velocity, and forimmediately returning the gyro rotor from the second to the firstposition.
 16. A two-wheeled vehicle as recited in claim 15 wherein thetipping sensor can sense the direction of tipping.
 17. A two-wheeledvehicle as recited in claim 15 further comprising a housing mounted onthe vehicle and encasing the gyro rotor, tipping sensor, precessionmeans and motor, said housing and gyro, tipping sensor, precession meansand motor defining a module mounted on the vehicle.
 18. A two-wheeledvehicle as recited in claim 17 wherein the housing comprises at least apartial vacuum chamber and wherein the gyro rotor is housed within saidat least partial vacuum chamber.
 19. A two-wheeled vehicle as recite inclaim 15 wherein the precession means comprises a motor.
 20. Atwo-wheeled vehicle as recited in claim 15 wherein the precession meanscomprises a solenoid coupled to the rotor.
 21. A two-wheeled vehicle asrecited in claim 15 wherein the solenoid means further comprises asecond solenoid coupled to the rotor, wherein one solenoid precesses therotor in one direction and the other solenoid precesses the rotor in theopposite direction.
 22. A two-wheeled vehicle as recited in claim 15wherein the gyro rotor returns to the first position under its owngyroscopic inertia.
 23. A two-wheeled vehicle as recited in claim 15wherein the tipping sensor comprises a gyro which maintains a positionrelative to a ground during tipping of the vehicle.
 24. A two-wheeledvehicle as recited in claim 15 wherein the tipping sensor comprises apendulum pivotally coupled to the vehicle, wherein the pendulum pivotsto maintain its position relative to the ground during tipping.
 25. Atwo-wheeled vehicle as recited in claim 15 wherein the tipping sensorsenses relative tipping from a balanced tilted position of the vehicle.26. A two-wheeled vehicle as recited in claim 15 wherein the tippingsensor comprises: a viscous coupling; a pendulum coupled to the viscouscoupling for maintaining it position relative to a ground during tippingof the vehicle; an arm coupled to the viscous coupling and extendingopposite the pendulum, wherein the viscous coupling allows the arm topivot relative to the pendulum; a first spring coupled to an end of thearm distally from the viscous coupling and to the vehicle, the firstspring being capable of providing a first force for pivoting the arm ina first direction; a second spring coupled to an end of the arm distallyfrom the viscous coupling and to the vehicle, the second spring beingcapable of providing a second force opposite the first force to the armfor pivoting the arm in a second direction opposite the first direction;a first contact coupled to the controller; and a second contact oppositethe first contact and coupled to the controller, wherein contact of thearm with the first contact is indicative of vehicle tipping in onedirection and wherein contact of the arm with second contact isindicative of vehicle tipping in the opposite direction.
 27. Atwo-wheeled vehicle as recited in claim 15 wherein the gyro rotor has aweight not greater than 10 lbs.
 28. A method for preventing the tippingof a two-wheeled vehicle coming to rest or when at rest comprising thesteps of: measuring the speed of the vehicle; sensing tipping of thevehicle; spinning a gyro rotor coupled to the vehicle about a spin axis;precessing the gyro rotor to precessed position from a non-precessedposition about a precession axis perpendicular to said spin axis and indirection to generate a force to counteract the tipping of the vehiclewhen the sensed speed of the vehicle is not greater than a predeterminedminimum speed and when tipping of the vehicle has been sensed; andimmediately returning the precessed gyro to the non-precessed position.29. A method as recited in claim 28 further comprising the steps ofcontinuously precessing and returning the precessed gyro rotor to thenon-precessed for maintaining the two wheel-vehicle balanced when comingto rest or when at rest.
 30. A method as recited in claim 28 wherein thestep of precessing comprises precessing of the spinning gyro only whenthe vehicle has tipped from a balanced position.
 31. A method as recitedin claim 30 wherein the balance position of the vehicle is a tiltedposition.
 32. A method as recited in claim 28 wherein the step ofsensing comprises the sensing of relative tipping from a balanced tiltedposition.